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+--- Thread: 85gr sierra hp fb with accurate 2520 load development (/showthread.php?tid=24596)
85gr sierra hp fb with accurate 2520 load development - mblackmon4 - 06-04-2022
So Im going to preface this with Im trying to use up components that I have the fewest of so thats how I started this.
I have 200ct 85gr sierra hp fb bullets, and some lapua brass, Tula small rifle primers and some older accurate 2520. I look in the western powders loading manual and lucky me 2520 is the fastest powder with that bullet that I have currently. However they list 33.9gr of powder as the max, WOW.
My rifle is a cz 527 with the 16 threaded barrel, I just got a wood stock to replace the factory plasticy houge junk, which is why Im doing new load development.
Started at 32.5gr and two seating depths 2.18 and 2.13
Everything has been Lee factory crimped
32.5gr a2520 lapua brass Tula small rifle primers
2.13 oal 2730fps
32.5gr a2520
2.18oal. 2770fps This is odd because its into the lands but sped up
Everything else is 2.182 oal
33gr a2520
2.182oal. 2800fps
33.5 a2520
2.182oal. 2815fps but first shot was 2870 other two were 2811 and 2817
33.9 a2520
2.182 2840fps
34.1 a2520
2.182oal. 2850 best group (.27 @100yds) but its full to the top of the neck and crunch a bullet down. This is over book max but 33.9 (book max) isnt much lower from the very top. Super weird but kinda cool, going to verify
All loads were under and inch but as I sped up the groups tightened
85gr sierra hp fb with accurate 2520 load development - lazyengineer - 06-04-2022
Neat. It's a good bullet. Intersting to see that you are crimping this thin jacket straight wall bullet in a bolt action rifle.
As to the increased velocity with the bullet hitting the lands, not super surprising since that will cause a pressure spike. Giving a faster and more complete powder burn. ... and a higher pressure spike to go with it. I don't really advise a hot load into the lands, personally.
Good to see all loads shot quite accurate.
Not surprised the hotter ones shot best. The hotter the load, thr more complete and consistent the powder burn will be.
85gr sierra hp fb with accurate 2520 load development - mblackmon4 - 06-04-2022
Ive started doing the Lee factory crimp die for most of my bullets even in bolt actions. I know its not needed but it seems to help lower my extreme spread on velocity and hasnt hurt my accuracy, if anything its tightened up groups some. I checked all my brass for pressure signs and it looks fine, gonna do some more playing with it today. Im thinking about trying accurate 2200 powder since it doesnt take as much powder and get close to the same velocities in the book. Im wondering if the faster powder will be better with the shorter barrel
85gr sierra hp fb with accurate 2520 load development - Harpoon1 - 06-04-2022
mblackmon4 Wrote:Ive started doing the Lee factory crimp die for most of my bullets even in bolt actions. I know its not needed but it seems to help lower my extreme spread on velocity and hasnt hurt my accuracy, if anything its tightened up groups some. I checked all my brass for pressure signs and it looks fine, gonna do some more playing with it today. Im thinking about trying accurate 2200 powder since it doesnt take as much powder and get close to the same velocities in the book. Im wondering if the faster powder will be better with the shorter barrel
A2460 is another good alternative double based spherical powder in that weight class. And supposedly, it considerably more temperature stable than A2520.
Still doing load development with it in the CZ 527 but, Ive already hit 3074 fps with 90 TNTs out a 23.5 barrel with zero signs of pressure on the brass!
85gr sierra hp fb with accurate 2520 load development - mblackmon4 - 06-04-2022
Harpoon Ive been reading some of your load development and that got me excited for mine. 3000fps is what the book says 33.9gr gets with a 20 ar15. Im at 5000 feet elevation using a labradar with 15% humidity and 75 degrees getting 2850 fps with a 16 barrel suppressed.
I have 200 90gr TNT to try after I burn all these lol.
85gr sierra hp fb with accurate 2520 load development - Harpoon1 - 06-04-2022
mblackmon4 Wrote:Harpoon Ive been reading some of your load development and that got me excited for mine. 3000fps is what the book says 33.9gr gets with a 20 ar15. Im at 5000 feet elevation using a labradar with 15% humidity and 75 degrees getting 2850 fps with a 16 barrel suppressed.
I have 200 90gr TNT to try after I burn all these lol.
Sounds good! What length Can are you using? Have you shot it unsuppressed with the same load to see what speed difference is?
85gr sierra hp fb with accurate 2520 load development - mblackmon4 - 06-04-2022
Harpoon1 Wrote:Sounds good! What length Can are you using? Have you shot it unsuppressed with the same load to see what speed difference is?
I havent shot it unsuppressed yet but I will because Im curious the speed difference as well. Im using a CGS Hyperion 9.5 can. Its big but light and quiet, I havent had this can all that long and it took a year and 1 day exactly to get approval in.
85gr sierra hp fb with accurate 2520 load development - Harpoon1 - 06-04-2022
mblackmon4 Wrote:I havent shot it unsuppressed yet but I will because Im curious the speed difference as well. Im using a CGS Hyperion 9.5 can. Its big but light and quiet, I havent had this can all that long and it took a year and 1 day exactly to get approval in.
Roger that. Should have some more data soon. Going higher with Lever and 120 Gold Dots. And same thing with A2460 and 90 TNTs. I sure wish I would have known they were going to discontinue the 527s, I would have bought 10 of them!
85gr sierra hp fb with accurate 2520 load development - mblackmon4 - 06-26-2022
Well I gave up on the accurate 2520 powder and switched to accurate 2200. Im loading 29.9gr of 2200 in a lapua case with a Tula small rifle primer, bullet is still the 85gr hp and its seated to 2.120. It was shooting cloverleafs an my 2915fps velocity had an extreme spread of 4.